1. Field of the Invention
This invention relates to a door machine having a chain disk locking mechanism, more particularly to an electric rolling door having a feature of opening/shutting in high speed, which is suitable for warehouse or garage needing frequent opening/shutting.
2. Description of the Related Art
Accompanying with the rising of Environment Protection and energy saving consciousness, for example, of avoiding cold air or warm air from leaking to outside, the opening/shutting of electric rolling door used for ordinary warehouse or garage becomes very frequent. Frequent opening/shutting may cause shorter lifetime of the rolling door. Further, in order to prevent cold/warm air from leaking to outside, there is a demand to increase the running speed of the electric rolling door.
Conventional electric door machine has a clutch which switches between the motor driven rolling and manual chain disk rolling. However, the clutch mechanism is complicated in structure and very expensive, what is more, the chances of failure are high. When the conventional electric door machine 1 as shown in FIG. 1 is in the condition of power blackout or failure in electric motor, manual operation of pulling the chain disk has to be conducted for door opening/shutting. Firstly, the switching chain 11 has to be pulled so as to change over the clutch (not shown in figure), and the chain 10 is pulled at the same time. In this manner, the rolling door can be rolled upward/downward by pulling the chain 10.
Thus it is an urgent demand to develop an electric door machine, which is easy in operation, speedy in rolling upward/downward, long lifespan, simple in structure, low-cost, and which may be switched between electric or manual modes without using a clutch mechanism.